The inline-eight engine is an internal combustion engine that consists of eight cylinders that are mounted along a crankcase in straight line. It is also known as straight eight. It has been built in overhead valve, overhead cam and side valve configurations.
The straight-8 helps in achieving good primary and secondary balance, as unbalanced primary and secondary moments or forces are not present. But, torsional vibration in crankshaft that is present in all the engines to some extent makes the requirement of harmonic damper in the crankshaft accessories. If this damping is not used then close to the rear main bearing journal, fatigue cracking can happen. This can further cause the failure of engine.
The inline-six engine also provides good primary and secondary balance. But, the straight-8 produces more number of power strokes in one revolution. Because of this, the straight-8 runs in a smoother manner when put under load as compared to inline six.



